Mechanism for supporting and automatically adjusting arc furnace electrodes



NOV. 20, w N MECHANISM FOR SUPPORTING AND AUTOMATICALLY ADJUSTING AN ARC FURNACE ELECTRODE Filed Sept. 11,-1944 Patented Nov. 20, 1945 MECHANISM FOR SUPPORTING AND AUTO- MATICALLY ADJUSTING ARC FURNACE ELECTRODES William Harvey Payne, Hinsdale, Ill. Application September 11, 1944, Serial No. 553,538

10 Claims. (01. 314-61) The present invention relates generally to mechanism for supporting. and automatically adjusting an arc furnace electrode. More particularly the invention relates to that type of electrode supporting and adjusting mechanism which is of the hydraulic variety and as its main or principal parts comprises (1) a vertically movable mounting for the electrode; (2) an upstanding cylinder which is disposed beneath the mounting and has an open upper end; (3) a piston which is mounted in the cylinder for vertical sliding movement and is operatively connected to the mounting by an upwardly extending piston rod; (4) a reservoir which contains liquid and is connected to the cylinder by a pipe system; (5) a reversible rotary metering pump which is interposed in the pipe system and is adapted when driven in one direction to supply liquid from the source into the cylinder and effect upward shift of the piston and electrode mounting and when driven in the opposite direction to remove liquid from the cylinder and cause lowering of the piston and mounting; and (6) a reversible electric motor which serves to drive the pump in either direction and is controlled automatically in response to variations in the electric power input to the electrode due to variations in the arcing gap of the electrode.

In practice it has been found that an electrode supporting and adjusting mechanism of the aforementioned type is subject to several objections, In the first place, when the piston and mounting are shifted upwards to their fullest extent asthe result of the metering pump being driven so as to cause liquid to be delivered from the reservoir into the cylinder, the pump, in connection with further drive thereof, pumps against a totally confined or solid body of liquid and, because of the resistance of such body, imposes such a load on the electric motor that the latter is caused to fail or burn out. Secondly, when the piston and electrode mounting are shifted downwards to their fullest extent as the result of reverse drive of the metering pump the pump, in connction with further or additional drive, runs dry and thereby results in the various operating parts of the pump being subjected to excessive wear. Thirdly, when the pump is automatically stopped as a result of correct or proper adjustment of the electrode the piston and electrode carrying mounting move slowly downwards due to the fact that the various clearances between the operating parts "of the pump permit seepage of the liquid under pressure back to the reservoir.

i The primary object of the present invention is to provide an electrode supporting and adjusting mechanism which is an improvement upon, and eliminates the defections of, previously devised mechanisms of the same general type or character by reason of the fact that it includes as part of the pipe system between the reservoir and the cylinder an arrangement of check and relief valves whereby, when the pump is driven after the piston and electrode carrying mounting reach the'limit of upward or downward shift, it operates to effect continuous circulation of liquid through the reservoir and when the pump is automatically stopped after adjustment of the electrode return or seepage of liquid under pressure through the pump back to the reservoir is positively precluded.

Another object of the invention is to provide an electrode supporting and adjusting. mechanism which is generally of new and improved construction and is characterized by high eniciency as well as simplicity of design.

A further object of the invention is to provide an electrode supporting and adjusting mechanism which is an improvement upon, and has certain inherent advantages over, that which is disclosed in, and forms the subject matter of, United States Letters Patent No. 2,296,734, granted to me on September 22, 1942.

Other objects of the invention and the various advantages and characteristics of the present electrode supporting and adjusting mechanism will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawing which accompanies and forms a part of this specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a diagrammatic view of an electrode supporting and adjusting mechanism embodying the invention; and

Figure 2 is an enlarged view of the arrange ment of the check and relief valves which are included in, and form a part of, the pipe system between the reservoir and the cylinder and serve when the pump is driven after the piston and mounting have been raised or lowered to their limit to effect continuous circulation of liquid through the reservoir, and also in connection with stoppage of the pump after an electrode adjusting operation to prevent back-flow or seepage of liquid under pressure through the pump and resultant gradual lowering of the piston and electrode carrying mounting.

The mechanism which is shown in the drawing constitutes the preferred embodiment of the invention and together with a roof equipped shell 3 and an electrode 4 forms an electric arc furnace.

- It serves to support and automatically adjust the electrode and as its principal parts or components comprises a vertically movable mounting 5 for the electrode, a cylinder 8, a piston I, a reservoir 8, a pipeasystem 8 between the reservoir and the cylinder, a valve arrangement Ill in thepipe system, a reversible rotary metering pump ii, and a reversible electric motor i2 for driving the pump. The shell 3 is of standardor conventional design and is lined with refractory material. It is adapted to hold a charge of metallic material to be melted and embodies at the upper portion thereof a spout (not shown) whereby the material, after melting thereof and in connection with tilting of the shell, may be poured into a ladle or other receptacle. The electrode 8 extends vertically and has the lower end thereof disposed within an aperture or hole in the shell roof. It is supplied with so-called electric power input by way of conductor means 83 and serves, when the furnace is in operation, to produce between it and the charge in the shell, an electric arc, the heat of which serves to melt or render molten the charge.

tending arm it and a vertical extension is. One

end of the arm is embodies releasable clamp means (not shown) for the upper end of the electrode t. The vertical extension i5 is connected to, and depends from, the other end of the arm id of the mounting b and is positioned adjacent the side wall of the furnace shell 3. It is tubular so far as design or construction is concerned and is mounted for vertical sliding movement by way of a roller equipped bracket it on the shell 3. The cylinder 6 extends vertically and is surrounded by the vertical extension it of the mounting 5. It is supported in any suitable manner by the bracket I6 and has an open upper end. The piston i is mounted in the cylinder for vertical sliding movement and embodies an upwardly extending piston rod H, the upper end of which extends through the open upper end of the cylinder and is connected to the upper end of the vertical extension it. When liquid under pressure is introduced into the lower end of the cylinder 6 as hereinafter described the piston together with the mounting 5 and the electrode i is shifted upwards. When the liquid is withdrawn from the lower end of the cylinder the piston, mounting and electrode, in response to the action of gravity, move downwards.

The reservoir 8 is positioned on the floor of the establishment in which the electric arc furnace is used and has in the lower portion thereof a column of any non-compressible liquid, such as oil. It is preferably in the form of a vertically extending pipe with closed ends. Air under pressure is confined in the upper portion of the reservoir and serves to subject the liquid in the reservoir to a force of such magnitude as to substantially counterbalance the piston, mounting and electrode. It is supplied to the upper end of the reservoir 8 by a pipe l8 which leads from a compressor or other source of air under pressure (not shown) cylinder 6 and has the valve arrangement l and the metering pump ii associated with it." As hereinafter described more in detail, the pipe system, valve arrangement and pump are so arranged that when the pump is driven in one direction it operates to supply liquid under pressure from the reservoir 8 into the lower end of the cylinder 6. In addition the arrangement is such that when the pump isdriven in the oppositedirection it operates to withdraw liquid from the lower end of the cylinder for electrode lowering purposes.

The pipe system 9 comprises a pair of aligned horizontally extending lower pipe sections is and V 20, a pair of horizontally extending upper pipe sections 2! and 22, a pair of laterally spaced vertically extending sectional pipes 23 and 24, and-a composite main pipe 25. The pipe section i9 is connected to, and extends outwards from, the lower end of the reservoir ii, as shown in Figure l. The pipe section 20 which is horizontally aligned with the pipe section it forms a continuation of the latter pipe section and is joined or connected to the outer end of the latter by a T-fitting 26, the cross branch of which extends upwards, as shown in Figure 2. The pipe section 2| is disposed over the pipe section is and, has one end thereof extending into the reservoir 8 and bent downwards. A vertically extending baflle 8 in the lower end of the reservoir 8 serves to separate the ends of the pipe sections i9 and 2! that are disposed inthe reservoir. The pipe section 22 overlies the pipe-section 20 and is in axial alignment with the pipe section 2|. The vertically extending sectional pipe 23 extends between the outer ends of the horizontally extending pipe sections i9 and 2! and has its lower end connected to the upwardly extending cross branch of the T-fltting 26. The upper end of the sectional pipe 23 is disposed adjacent the adjoining ends of the upper pipe sections 2| and 22. The vertically extending sectional pipe 26 extends between the outer ends of the horizontally extending pipe sections 29 and 22 and has its lower end connected to the outer end of the pipe section 26 by an elbow 21. The composite main pipe 25 is connected to, and extends between, the central portion of the sectional pipe 26 and the lower end of the cylinder 6 and includes a flexible hose 28 in order that the cylinder is free to tilt with the shell 3 in connection with a molten metal pouring operation. The end of the main pipe 25 that is remote from the cylinder 6 is connected to the central portion of the vertically extending sectional pipe 2s by way of a e-branch fitting 29.

The valve arrangement l0 comprises a pair of check valves 30 and ti and a pair of relief valves 32 and 33. The check valve 30 is interposed in, and connected to, the lower end of the vertically extending sectional pipe 23 and consists of a vertically elongated tubular body 30'- and a ball valve 30. The ball valve normally rests on an annular seat 32 in the lower end of the body 30. The check valve 3i is connected to, and interposed in, the lower end of the vertically extend- 5 ing sectional pipe 24. As shown in Figure 2 it is located between the elbow 21 and the i-branch fitting 29 and consists'of a vertically elongated tubular body 3! and a ball valve 3|. The ball valve 3 l normally rests on an annular seat 3! in ,0 the lower end of the body 3|. The relief valve 32 is connected to the upper end of the vertically extending sectional pipe 23 and the adjoining ends of the aligned horizontally extending pipe sections 2| and 22 and comprises a vertically elongated body 32*? and a ball valve 32". The lower end of the body is connected to the upper end of the pipe 23 and the upper end of the body isprovided with a pair of laterally extending aligned internally threadedbranches for connection to 7 the adjoining ends of the pipe sections 2| and 22. The ball valve 32" normally rests on an annular seat 32 in the lower end of the body 32 of the through the upper end of the valve body 32' and permits adjustment of the load of the spring in response to turning thereof. The relief valve 33 extends between, and is connected to, the outer end of the pipesection 22 and the upper end of the vertically extending sectional pipe 24 and comprises a vertically elongated tubular body 3 3 and a ball valve 33'. The lower end of the body 33 is connected to the upper end of the pipe 24 and embodies an annular seat 33 on which the ballvalve 33 normally rests. The upper end of the body 33 is provided with a laterally extending internally threaded branch which is connected to the outer end of the pipe section 22. A compression spring 33 in the body 33 urges the ball valve 33 against its seat 33. The upper end of the spring 33 abuts against the lower end, of a screw 33 which, as shown in Figure 3, extends through the upper end of the valve body 33?. Turning of the screw 33 serves to effect adjustment of the loading of the spring 33 The reversible rotary metering pump I I is disposed between the vertically extending sectional pipes 23 and 24 and is of the gear pump variety. It is driven by the reversible electric motor I2 and comprises a casingI I and a pair of rotary meshing gears II". The pump casing II is provided on opposite sides of the gears with a pair of diametrically opposite ports. One of the ports is connected to the central portion of the sectional pipe 23 by a pipe section 34 and a T-fltting 35 and the other port is connected to one of the branches of the ii-branch fitting 29 by a pipe section 36. When the pump I I is driven so as to supply liquid under pressure into the cylinder 6 for electrode raising purposes the flow of liquid is as follows: pipe section I9, T-fitting 23, check valve 30, T- fitting 35, pipe section 34, pump II, pipe section 36, fitting 29 and main pipe 25. When the pump is reversely driven in order to effect lowering of the electrode 4 the liquid flows in the following manner: main pipe 25, fitting 29, pipe section 36, pump I I, pipe section 34, T-fitting 35, relief valve 32, and pipe section 2|. When the pump is at rest the two check valves and the two relief valves lock the liquid under pressure in the main pipe 25 and hence there is no seepage or leakage of liquid under pressure back to the reservoir 8 and gradual lowering of the piston, mounting and electrode. The springs of the two relief Valves 32 and 33 are so loaded that the ball valves thereof are only unseated when subjected to greater pressure than the normal working pressure in the main pipe 25. In the event that the pump is driven after the piston reaches the limit of upward or downward shift the liquid in the pipe system is recirculated back to the reservoir 8. When the pump is driven after the piston 'I is shifted upwards to its limit or fullest extent the liquid in the pipe system recirculates in the following manner: pipe section I9, check valve 30, T-fitting 35, pipesection 34, pump I I, pipe section 36, branch fitting 29, relief valve 33, and pipe sections 22 and 2|. Reverse drive of the pump after the piston I is shifted downwards to its full limit or extent causes the liquid in the pipe system to recirculate in the following manner: pipe section I9, T-fitting 26, pipe section 20, elbow 21, check valve 3|, fitting 29, pipe section 35, pump II, T-fitting 35, relief valve 32, and pipe section 2]. As the result of the arrangement of the check and relief valves there is no return of the liquid under pressure through the pump back to the reservoir when the pump is stopped and there is a continuous circulation of liquid through the pump and reservoir when the pump is driven after the piston is shifted upwards or downwards to its limit or fullest extent. By positively locking the liquid under pressure in the main pipe 25 of the pipe system when the pump is stopped the piston, mounting and electrode are locked in place and the electrode 4 is hence maintained at its desired or proper position. By reason of the fact that there is a continuous circulation or recirculation of liquid through the pump and reservoir when the piston reaches its upperlimit of shift the pump does not pump against a confined or solid body of liquid and hence does not impose such a nected to drive the operating parts of the pump..

It is of the reversible type, as hereinbefore pointed out, and is automatically controlled by an electric control system 31 which, as well understood in the art, is responsive to variations in the electric power in-put due to variations in the arcing gap of the electrode and automatically effects drive of the motor in one direction or the other depending upon whether the demand is for raising or lowering of the electrode. In other words, the electric control system 31 translates changes in voltage and amperage into a demand that the electrode be raised or lowered and automatically effects drive of the motor in either direction depending upon whether the demand is for raising or lowering the electrode.

The herein described electric arc furnace mechanism effectively and efficiently fulfills its intended purpose and is characterized by simplicity and long life. It is essentially simple in design and hence may be manufactured or produced at a comparatively low cost.

The invention is not to be understood as re-' stricted to the details set forth since these may be modified within the scope of the appended claims without departing from the spirit and scope of the/invention.

This application is a continuation in part of United States patent application Serial No. 502,- 4

649, filed September 16, 1943, and entitled Means for automatically adjusting arc furnace electrodes. I

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. An electric arc furnace comprising a vertically movable mounting, an electrode carr ed by the mounting and provided with current supplying means, vertically adjustable supporting means for the mounting in the form of cylinder and piston elements arranged for relative sliding from and to the source.

2. An electric arc furnace comprising a vertically slidablemounting, an electrode carried by the mounting and provided with means for supplying it with electric power input, vertically adjustable supporting means for the mounting in the form of an upstanding cylinder, and a, piston mounted in the cylinder for vertical slidin movement to a limited extent in either direction and operatively connected to the mounting, a

source of liquid, a pipe system between the source and the cylinder, a reversible rotary pump disposed in the system and adapted when driven in one direction to supply liquid from the source to the cylinder and effect upward shift-of the mounting and when driven in the opposite direction to remove liquid from the cylinder and ef-' fect downward shift of said mounting and electrode, means for driving the pump in either direction, controlled automatically in response to variations in said electric power input, said pipe system including a pipe between the source and the pump and a pipe leading to the source and having a pair of inlet branches leading from opposite sides of the pump, and a valve arrangement in the form of a check valve in the first mentioned pipe and a pair of relief valves in the branches of the second mentioned pipe, adapted when the pump is idle to lock the liquid in the cylinder and when the pump is driven in said one direction after sliding movement of the piston to its fullest extent to connect said pump so that it is capable of pumping liquid from and to the source.

3. An electric arc furnace comprising a vertically movable mounting, an electrode carried by the mounting and provided with current supplying means, vertically adjustable supporting means for the mounting in the form of'cylinder and piston elements arranged for relative sliding movement to a limited extent in either direction, a source of liquid, a pipe system between said source and the cylinder element, a reversible rotary pump disposed in the system and adapted when driven in one direction to supply liquid from the source to the cylinder element and eflect vertical shift of the mounting and electrode in one direction and when driven in the opposite direction to remove liquid from the cylinder element and effect vertical shift of said mounting and electrode in the opposite direction, means for driving the pump in either direction, controlled automatically in response to variations in the arcing gap of the electrode, and a valve arrangement in the form of a pair of check valves and apair of relief valves, associated with, and forming a part of, the pipe system and arranged and adapted when the pump is stopped to lock the liquid in thecylinder element and cally movable mounting, an electrode carried by 75 essence the mounting and provided with current supplying means, vertically adjustable supporting means for the mounting inthe form of cylinder and piston elements arranged for relative sliding movement to a limited extent in either direction. a, source of liquid, a pipe system between said source and the cylinder element, a reversible metering gear pump disposed in the system and adapted when driven-in one direction to supply liquid from the source to'the cylinder element and effect vertical shift of the mounting and electrode in one-direction and when driven in the opposite direction to remove liquid from the cylinder element and efiect shift of the mounting and electrode-in the opposite direction, a reversible electric motor adapted to drive the pump in either direction and controlled automatically in response to variations in the arcin gap of the electrode, said pipe system including a pair of pipes each leading to the source and having a pair of branches leading to opposite sides of the pump, and a valve arrangement in the form of a pair of check valves in the branches of one of the pipes of the system and a pair of relief valves in the branches of the other pipe, adapted when the pump is stopped to lock the liquid in the cylinder element and when the pump is driven in either direction after relative sliding of the elements to their fullest extent to permit the pump to pump liquid from and to the liquid source.

5. An electric arc furnace comprising a vertically movable mounting, an electrode carried by the mounting and provided with current supplying means, vertically adjustable supporting means for the mounting in the form of cylinder and piston elements arranged for relative sliding movement to a limited extent in either direction, a source of liquid, a pipe system between said source and the cylinder element, a reversible rotary pomp disposed in the system and adapted when driven in one direction to supply liquid from the source to the cylinder element and effect vertical shift of the mounting and electrode in one direction and when driven in the opposite direction to remove liquid from the cylinder element and effect vertical shift of said mountin and electrode in the opposite direction, means for driving the pump in either direction, controlled automatically in response to variations in the arcing gap of-the electrode, and a valve arrangement in the form of a pair of check valves, and a relief valve associated with, and forming a part of, said pipe system and arranged and adapted when the pump is stopped to lock thethe mounting and provided with means for sup-- plying it with electric power input, vertically adjustable supporting means for the mounting in the form of anupstanding cylinder and a piston mounted in the cylinder for vertical sliding movement toa limited extent in either direction and operatively connected to the mounting, a source of liquid, a pipe system between the source and the cylinder, a reversible rotary pump disposed in the system and adapted when driven in one direction to supply liquid from the source to the cylinder and effect upward shift of the mounting and when driven in the opposite direction to remove liquid from the cylinder and eflect downward shift of said mounting and electrode, means for driving 'the pump in either direction, controlled automatically in response to variations in said electric power input, said pipe system including a. pipe leading from the source and having a pair of outlet branches leading to opposite sides of the pump. and a second pipe extending between, and serving to connect, the source and pump, and a valve arrangement in the form of a pair of check valves in the branches of the first mentioned pipe and a relief valve in said second pipe, adapted when the pump is stopped to lock the liquid in the cylinder and when the pump is driven in said other direction after slid ing movement of the piston to its fullest extent to connect the pump so that it is capable of pumping liquid from and to the source.

7. An electric arc furnace comprising a verti cally slidable mounting, an electrode carried by the mounting and provided with means for sunplying it with electric power input, vertically adjustable supporting means for the mounting in the form of an upstanding cylinder, and a piston mounted in the cylinder for vertical sliding movement to a limited extent in either direction and operatively connected to the mounting, a source of liquid, a pipe system between the source and the cylinder, metering pump means disposed in the system and adapted when actuated in a certain manner to supply liquid from the source to the cylinder and effect upward shift of the mounting and electrode and when actuated in a different manner to remove liquid from the cylinder and effect downward shift of said mounting and electrode, means for effecting actuation of said metering pump means in either manner, controlled automatically in response to variations in the electric power input, said pipe system including a pipe between the source and the, metering pump means and a pipe leading to the source and having a pair of inlet branches leading from opposite sides of said metering pump means, and a valve arrangement in the form of a check valve in the first mentioned pipe and a pair of relief valve; in the branches of the second mentioned pipe adapted when the metering pump means is idle to lock the liquid in the cylinder and when said metering pump means is actuated in said certain manner after sliding movement of the piston to its fullest extent to connect the metering pump means so that it is capable of pumping liquid from and to the source.

8. An electric are furnace comprising a vertically slidable mounting, an electrode carried by the mounting and provided with means for supplying it with electric power input, vertically ad- Justable supporting means for the mounting in the form of an upstanding cylinder and a piston mounted in the cylinder for vertical sliding movement to a limited extent in either direction and operatively connected to the mounting, a source of liquid, a pipe system between the source and the cylinder, metering pump means disposed in the system and adapted when actuated in a certain manner to supply liquid from the source to the cylinder and effect upward shift of the mounting and electrode and when actuated in a different manner to remove liquid from the cylinder and effect downward shift of said mounting and electrode, means for effecting actuation of said metering pump means in either direction. controlled automatically in response to variations in said electric power inpu said pipe system including a pipe leading from the source and having a pair of outlet branches leading to opposite sides of the metering pump means and a second pipe extending between and serving to connect the source and metering pump means, and a valve arrangement in the form of a pair of check valves in the branches of the first mentioned pipe and a relief valve in said second pipe adapted when the metering pump means is stopped to lock the liquid in the cylinder and when the metering pump means is actuated in said different manner after sliding of the piston to its fullest extent to connect the metering pump means so that it is capable of pumping liquid from and to the source.

9. An electric arc furnace comprising a vertically movable mounting, an electrode carried by the mounting and provided with means for supplying it with electric power input, vertically adjustable supporting means for the mounting in the form of coacting piston and cylinder elements arranged for relative vertical sliding movement in either direction, a source of liquid, a pipe system between the source and the cylinder element, metering pump means disposed in the system and adapted when actuatedin a certain manner to supply liquid from the source to the cylinder element and effect vertical shift of the mounting and electrode in one direction and when actuated in a different manner to remove liquid from the cylinder element and effect vertical shift of said mounting and electrode in the opposite direction, means for effecting actuation of said metering pump means in either manner, controlled automatically in response to variations in the electric power input, said pipe system including a pipe leading from the source to one side of the metering pump means and a pipe leading from said one side of the metering pump means to the source, and a valve arrangement in the form of a check valve in the first mentioned pipe and a relief valve in the second mentioned pipe, adapted when the metering pump means is ineffective to lock the liquid in the cylinder element.

10. An electric arc furnace comprising a vertically slidable mounting, an electrode carried by the mounting and provided with electric current supplying means, vertically adjustable supporting means for the mounting in the form of coacting piston and cylinder elements arranged for relative vertical sliding movement in either direction, a source of liquid, a pipe system between the source and the cylinder element, a reversible rotary pump disposed in the pipe system and adapted when driven in one direction to supply liquid from the source to the cylinder element and effect vertical shift of the mounting and electrode in one direction and when driven in the opposite direction to remove liquid from the cylinder element and effect vertical shift of said mounting and electrode in the opposite direction, means for driving the pump in either direction, controlled automatically in response to variations in the arcing gap of the electrode. said pipe system including a pipe leading from the source to one side of the pump and a pipe leading from said one side of the pump to the source. and a valve arrangement in the form of a check valve in the first mentioned pipe and a relief valve in the second mentioned pipe, adapted when the pump is at rest to lock the liquid in the cylinder element.

WILLIAM HARVEY PAYNE. 

